I think some way, some how, someone needs to go into some serious detail about AV Foundation. A think in FCPX that sort of looks like something analogous to something in FCP7, really isn't in terms of what's going on in the code. Much of this has to do with the move from Quicktime to AV Foundation. Even what looks like a "sequence" in FCPX really is radically different than the similar looking thing in FCP7.

The differences between Quicktime and AV Foundation may make some heads spin but it really needs to be explained in nonprogramer terms for professional editors.